Abstract
The applicability limits of the small complex phase perturbation (Rytov) theory for laser light propagation in soft biological tissues have been tackled. We have found that for typical coherent optical waves and for several types of optically soft biological tissues with known spatial power spectra, the weak regime of light-field fluctuations is limited to propagation distances of tens of microns. This result is in striking difference with oceanic or atmospheric propagation of light for which weak fluctuation regime may hold for tens of meters in the former case and kilometers in the latter. Furthermore, the scintillation indexes of plane, spherical, and Gaussian-beam waves are investigated in depth. Our results are envisioned to find applications in optical/infrared techniques for soft tissue diagnostics.
